A panoramic image is an image with a wide field of view. A panoramic image can have a field of view up to an entire sphere, that is 360 degrees in the horizontal dimension and 180 degrees in the vertical dimension.
Panoramic images can be computer generated using mathematical models, or they can be produced by seaming together a number of photographically captured images. The number of images which must be seamed to form a panorama is determined by the field of view of each of the images being seamed. For example a fisheye lens can capture a very wide field of view, and as few as two such images can be seamed to form a spherical panorama.
Computer programs are available which match the edges of images and which join a number of images to form a panorama. For example U.S. Pat. Nos. 5,023,925 and 5,703,604 describe a system for capturing images, seaming the images into panoramas, and for viewing selected portions of the panoramic images. Dodeca L.L.C., located in Portland, Oreg., commercially markets a system for capturing images using a multi lens camera. In the Dodeca system the images are recorded on video tape using the conventional NTSC video standard.
Co-pending patent application Ser. No. 09/310,715, filed May 12, 1999 describes how a series of panoramic images can be made into a panoramic movie which simulates movement through three dimensional space. In order to make a panoramic movie images must be captured, recorded, and seamed. The prior art system for capturing and storing images a series of images suitable for seaming into panoramas, captured and stored the images using the conventional NTSC video format. The analog NTSC format signals were later converted to digital signals.
The NTSC video format utilizes interlaced fields. If images are captured and stored using the interlaced NTSC format, prior to seaming, the interlacing must be eliminated. This can be done utilizing a variety of techniques, for example, if the images were captured at 60 interlaced fields per second, every alternate field can be ignored resulting in 30 non-interlaced digital images per second. Alternatively, each two adjacent interlaced fields can be combined into one non-interlaced digital image. However, irrespective of how the interlacing is eliminated, data is lost or undesirable inter-frame artifacts are introduced into the resulting non-interlaced images.
The present invention eliminates the problems introduced by the NTSC format by capturing and storing the original images utilizing digital progressive frame (that is non-interlaced) technology. Since the present invention initially captures images utilizing digital progressive frame technology, a sequence of panoramas made from images captured and recorded with the present invention can be displayed as a panoramic movie which faithfully represents rapid movement through multidimensional space.
It is known that a cubic representation is a particularly efficient technique for representing a panorama. That is, storing six images that collectively represent an entire spherical panorama is particularly efficient with respect to the amount of memory required to store such a panorama. The present invention provides an image capture device that inherently takes advantage of the storage efficiencies inherent in a cubic representation.